It is known in the art to provide equipment for detecting nuclear radiation levels, including personal-use devices that can be mounted on or carried by a user. Such equipment provides the benefit of identifying and usually quantifying the nuclear radiation level in an area where the user is located, which can be of particular value if the user is in a location susceptible to potentially dangerous radiation exposure. As the equipment can provide an early warning of hazardous radiation levels, this allows the user to vacate the location or don suitable protective gear.
However, while there are many available technologies capable of such use, very few lend themselves to widespread application. This is primarily due to the expense of such solutions, the complexity of use and/or the bulk of the necessary equipment. Radiation detectors are intended to protect users from unsafe radiation exposure, but the failure to achieve widespread deployment of existing technologies hinders that ultimate goal. It is clear that the cost and complexity of specialized equipment presents a significant problem.
It has been recognized that certain image sensors, such as charge-coupled devices (CCD) and complementary metal-oxide-semiconductor devices (CMOS), can be used to identify nuclear radiation levels. Such image sensors have achieved ubiquitous distribution through their use in digital cameras and the incorporation of digital cameras in various consumer electronic products such as cellular telephones. The concept of employing digital cameras for nuclear radiation detection purposes has been noted, and software has been made available for download to enable this. For example, an application for Android™ platform devices is available from Rolf-Dieter Klein at http://www.appbrain.com/app/radioactivitycounter/com.rdklein.radioactivity, and an application for iPhone™ devices is available from WikiSensor at http://wikisensor.com. To use these applications, however, a user must cover the digital camera lens with an opaque tape such as black electrical tape, to prevent visible light from contacting the sensor, which then allows only higher energy photons such as those generated by radioactive sources to penetrate to the sensor. If the tape is permanently employed, the standard image capture functionality of the camera is lost; alternatively, if the tape is removed, the nuclear radiation detection functionality is lost. Also, such known software must be running constantly in the foreground, impacting the use of other applications and draining device battery power reserves.
What is needed, therefore, is a cost-effective solution that can be employed with ubiquitous, mobile consumer electronic devices, taking advantage of the ability of digital camera sensor technology while alternately enabling camera functionality and nuclear radiation detection functionality.